The Fourth Amendment protects us from “unreasonable” government searches of our persons, houses, papers and effects. How courts should determine what is and isn’t reasonable in our increasingly digital world is the subject of a new amicus brief we filed today in San Francisco federal court.

At issue is historical cell site data—the records of the cell towers a customer’s cell phone connects to. The government has long maintained that it’s unreasonable for customers to expect those records to remain private. As a result, the government argues it does not need a search warrant to obtain historical cell site records from cell phone providers.

Updated: July 1st at 6:30PM to add information about traffic correlation attacks.

We posted last week about the Tor Challenge and why everyone should use Tor. Since we started our Tor Challenge two weeks ago we have signed up over 1000 new Tor relays. But it appears that there are still some popular misconceptions about Tor. We would like to take this opportunity to dispel some of these common myths and misconceptions.